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Chlorinated water, pesticides linked to food allergies

A chemical used in pesticides, antibacterial soap and water chlorination increases people’s risk of developing food allergies, according to a study conducted by researchers from the American College of Allergy, Asthma and Immunology (ACAAI) and published in the college’s journal, Annals of Allergy, Asthma and Immunology.

“Our research shows that high levels of dichlorophenol-containing pesticides can possibly weaken food tolerance in some people, causing food allergy,” lead researcher Elina Jerschow said. “This chemical is commonly found in pesticides used by farmers and consumer insect and weed control products, as well as tap water.”

Approximately 15 million people suffer from food allergies in the United States alone. The number increased 18 percent between 1997 and 2007.

“Previous studies have shown that both food allergies and environmental pollution are increasing in the United States,” Jerschow said. “The results of our study suggest these two trends might be linked, and that increased use of pesticides and other chemicals is associated with a higher prevalence of food allergies.”

The most common food allergies are to eggs, fish, milk, peanuts, shellfish, soy, tree nuts and wheat. Reactions can range between mild (such as rashes or tingling in the mouth), moderate (such as hives, ashtma or gastrointestinal problems) or extreme (such as anaphylaxis, which affects the whole body and includes a potentially life-threatening swelling of the throat and tongue). For that reason, ACAAI advises people who suffer from food allergies to carry two doses of prescription epinephrine with them at all times.

80 percent increased risk

The researchers examined data on 10,348 people who had participated in a U.S. National Health and Nutrition Examination Survey. Of 2,211 people who had detectable urine levels of the chemicals known as dichlorophenols, 411 suffered from at least one food allergy and 1,016 from at least one environmental allergy. The rate of food allergies among participants with high urine levels of dichlorophenols was 80 percent higher than in the general population.

The findings point to the need for more research into the health and environmental effects of pesticides, said Kenneth Spaeth of North Shore University Hospital in Manhasset, N.Y., who was not involved in the study.

“The immune system begins developing in fetuses and continues its development through childhood,” he said. “Therefore, it is plausible that exposure to these pesticides during this development could alter the immune system in ways that could increase the risk of allergies.”

Avoiding chlorinated water could help reduce dichlorophenol exposure, but Jerschow warns that pesticides are probably a much more significant source. Therefore, he recommends eating fruits and vegetables that have been exposed to fewer chemicals.

Antibacterial products (such as soaps, toothpastes and cosmetics) containing the chemical triclosan are another significant source of dichlorophenol exposure for many people. Triclosan often breaks down into dichlorophenol.

The study is not the first to link chlorine chemicals to allergies. A 2010 study in the European Respiratory Journal found that exposure to chlorinated pools significantly increased children’s risk of respiratory allergies.